The proposed research is concerned with the nature of the interaction of linguistic information during sentence comprehension. Specific focus is on the effects of strong biasing lexical contexts upon processing of lexical ambiguities. In attempting to determine whether such contexts direct access of the relevant meanings of an ambiguity (in which case the 'other' meaning of the ambiguity is never accessed) or whether such contexts only have their effect after access of all meanings of the ambiguity, a newly developed task is being employed. This new task is necessitated by the lack of any current methodology which has the flexibility to measure strong context effects during comprehension. The task involves listening to (and comprehension of) sentences containing ambiguities and, concurrently, judgment of whether a visually displayed string of letters is a word or not. Presentation of the visual word (which is related to one or another of the readings of the ambiguity) occurs simultaneously with the end of the auditorily presented ambiguity. A pilot study has suggested that the task is sufficiently flexible and sensitive to examine the question of context effects, and has, tentatively, indicated that contexts may have their effects only after access of all meanings of the ambiguity. The proposed research will further examine the results of this pilot study, expanding the scope of the investigation to include context effects upon unequibiased ambiguities and non-ambiguous words. Further, the proposed research will examine the time course and nature of the process by which context helps in the decision process which resolves ambiguities following their access. In all of the (4) proposed studies, the new task will be utilized; its flexibility allows testing of relative activation of different meanings of the ambiguity at any desired point during comprehension of the sentence. Finally, some examination of the task itself (compared to other on-line tasks) will be undertaken so that a more adequate theory of on-line comprehension tasks can be achieved.